Capacitor question

[Dave A]

I have a question in regards to capacitance. On a KP-480 crossover there are two 100uf and a 1uf soldered together in parallel. Now with the tolerance at best at 5% why so particular on 201 total uf when a 5% tolerance goes way past the 1uf capacitor?  Can I just use two 100 uf caps and forget the 1 uf cap? Adding to this I can get a 10% tolerance  200 uf cap and just use one. I see on a Crites AL-3 the use of two 68 uf caps in parallel and they are 10% tolerance caps from Parts Express ( or at least the same thing is sold there ) so what is the best route to go here?

[Full Range]

This answer is from a site that reviews capacitors 

 

 

Quote

Technical specifications (according to manufacturer): "Metallised polypropylene, radial capacitor, designed for LC/RC filter circuits, coupling and de-coupling at high frequencies."

Sound: Many years ago I was tipped by Klaus Witte of Germany to try this capacitor as a small parallel cap for the Mundorf MCap Supreme. I tried them as a parallel cap for the tweeter series caps in my Progress speaker and I must say I was very impressed! To get straight to the point they don't change a Supreme into a Supreme Silver-Oil but they really do clear things up. I must admit I was sceptical at first as the value is only 10nF (0,01uF) - and the caps I was using at the time totalled to 12,6uF. The difference is most noticeable with classical music but also good quality recordings of jazz and fusion benefit: No change in sound stage width or depth but there is more concert-hall acoustics that let you get into the recording more. Not as liquid as a Mundorf Silver Oil but they did take away the slightly grainy edge from the Mundorf Supreme's. A noticable gain in clarity and transparency making instruments better separable from each other, the violins in an orchestra become a group of individual violins instead of one mass. Jazz drum brushes sound more like a brush than a "shush.

 

 

This is the link  

http://www.humblehomemadehifi.com/Cap.html

 

And the capacitors being talked about 

Vishay MKP1837 / 0,01uF MKP 100VDC - 1% tolerance

 

I have employed these capacitors in my crossover build 

 

[pzannucci]

Doesn't make much sense to add a film 1uf to the woofer low pass IMO.  Not directly in the path.

[moray james]

the 1uf cap may be there as a better sounding bypass cap for the two larger units though a 0.1 uf would do as well. Just because things are not in the signal path means much of anything as to how they may or may not sound. People will tell you that a cap to ground has no impact on the sound, they are usually people who have either not tried or who have such low resolution systems they cannot tell much of anything. Even folks with expensive rigs can have them so badly set up or uses such bad combinations of cables and power cord and or have awful rooms and or lack of ears... you see where this goes. Everything make a contribution to the sound. There is no magic bullet when making improvements you need to learn what are your biggest problems are and start there first. Dropping sota bypass caps into a junk AVR is not going to help much. Audio nirvana is a long journey of learning and patience. Enjoy your time traveling the path.

[Deang]

The capacitors in question are in the high pass section of the network. I've never seen Klipsch add a bypass cap before, but there it is.

[Dave A]

OK here is the schematic for the KP-480. The caps that are on there do not have a negative or positive marking and the 1 uf cap is one of those old blue Mexico ones. So therefore nothing special as far as I can see. I know in machining there is tolerance stackup where every little discrepancy leads to overall loss of tolerance so you eliminate them where you can IF it is required to meet specs.  So I am back to asking why a 1 uf on top of two 100 uf? Is a 1/2 percent cap value relative to the aggregate really meaningful when the tolerance slop is far greater? Replacing these and duplicating what is there is not a problem I just don't understand why it was done this way and what difference that 1 uf cap makes.

KP-480.pdf

[babadono]

30 minutes ago, Deang said:

The capacitors in question are in the high pass section of the network. I've never seen Klipsch add a bypass cap before, but there it is.

So basically they're just blocking DC to the tweeter? I mean isn't that a lot of capacitance in series with a tweeter?

[Deang]

Apparently, the KP-480 is a passive subwoofer - there's only one driver. 

[efzauner]

"not directly in the audio path"   is non-sequitur. Just because the cap is not in series with the woofer does not mean its value and performance is not part of the filter transfer function. Nobody says that an inductor in parallel with a tweeter in a 12dB/octave LC network is "not directly in the audio path"  

 

In the case of the KP480, those capacitors form a 150Hz High Pass 6dB/octave passive crossover in case you want to add the subs to an existing system with only one channel amp. 

You connect the output of the amp to the sub in, and then your wideband speakers to the HF output. They only get frequencies above 150Hz. 

You could use a good quality 200uF also.  I gather they used 2x100uF because a single 200uF of audio quality may be hard to find. These subs are for Pro use and the power handling is considerable. You would want a low ESR cap here.  The small bypass may be there to counter some stray inductance in the larger caps that would attenuate higher frequencies up to 20KHz.  I doubt it is to reduce ESR as the big caps typically are power supply caps and have generally lower ESR than smaller caps. 

 

With the low cost of modern digital pro power amps with built in electronic crossovers, I gather the passive KP480 may be less used now.